As per the Torts Prof Blog, Justice Scalia in his capacity as Circuit Justice for the 5th Circuit has issued a stay in Philip Morris v. Scott, a tobacco class action in Louisiana. This was a case brought on behalf of all Louisiana smokers on a fraud theory. Justice Scalia writes in his opinion - available here - that the Louisiana court ruled that the plaintiffs didn't need to prove individual reliance if all they were asking for was class-wide relief in the form of a smoking cessation fund. The defendants argue that this was a violation of their due process right to present "every available defense." Plaintiffs argue that defendants simply don't have this defense as matter of substantive law. Importantly, Scalia writes:

The apparent consequence of the Court of Appeals holding is that individual plaintiffs who could not recover had they sued separately can recover only because their claims were aggregated with others' through the procedural device of the class action.

561 U.S. __ (2010). If the court grants cert on this and the Dukes v. Wal-Mart case, it will be a banner term for class action scholars. A very nice description of the case (more thorough than I have provided) can be found on SCOTUSblog.